Method of and means for facilitating a sealing of end flaps of a film

ABSTRACT

A method of tensioning end flaps of a film which has been already sealed along at least one of the top, bottom, front and back of an object to be packed. This method consists in establishing a stream of air flowing toward the end flap along at least the top of the object, and training the end flaps of the film along the air stream. Means to carry out this method comprises a plurality of air injection nozzles extending towards the end flaps of the film along at least the top of the object.

United States Patent [191 Sato [ METHOD OF AND MEANS FOR FACILITATING ASEALING OF END FLAPS OF A FILM [75] Inventor: Yoshimasa' Sato, Yokohama,

Japan [73] Assignee: Ikegai Tekko Kabushiki Kaisha, Tokyo, Japan [52]US. Cl 53/124 C, 53/373, 53/385 [51] Int. Cl B65b 1/24, B65b 7/06, B65b43/34 '[58] Field of Search 53/33, 39, 25, 385,

53/373, 388, 124 C, 124 D, 386, 124 A, 124

CC; 271/74; 214/1 AR, 1 BE [56] References Cited UNITED STATES PATENTS3,019,583 2/1962 Sylvester et a1 53/373 3,066,459 5 12/1962 Goodwin eta1. 53/39 X [451 Aug. 21, 1973 3,123,955 3/1964 Weissensee et a1 53/33 X3,597,900 8/1971 Scott 53/39 X 3,200,563 8/1965 Berghgracht 1 53/3733,220,161 11/1965 Lohse et a1. 53/373 3,260,170 7/1966 Barraclough53/385 X 3,411,770 11/1968 Albright 1 214/1 BE 3,136,539 6/1964 Lyman271/74 X 7 Primary Examiner-Travis S. McGehee Assistant Examiner-HoraceM. Culver Attorney--Wenderoth, Lind & Ponack [57] ABSTRACT I A method oftensioning end flaps of a film which has been already sealed along atleast one of the top, bottom, front and back of an object to be packed.This method consists in establishing a stream of air flowing toward theend flap along at least the top of the object, and training the endflaps of the film along the air stream. Means to carry out this methodcomprises a plurality of air injection nozzles extending towards the endflaps of the film along at least the top of the object.

2 Claims, 18 Drawing Figures PAIENIEBIIBN an SHEUIUFZ YOSH IMASA SATO 1NVENTOR ATTORNEY s YOSHIMASA SATO INYENTOR METHOD OF AND MEANS FORFACILITATING A SEALING OF END FLAPS OF A FILM BACKGROUND OF THEINVENTION This invention relates to a method of facilitating sealing ofend flaps of a film which has already been sealed 7 shape with oppositeend openings. Therefore, the sealing of the end flaps of the film isneeded to close the end openings of the film to complete the sealing andpacking of the object. In the case of sealing the end flaps of the film,it has been the practice to secure them together by means of a heat sealafter suitably folding the end flaps of the film or without folding.However, where a non-rigid film is employed to wrap the object, theupper end flap of the film bends down due to its ,own weight. Thiscauses inconvenience in the next step of the packaging operation,resulting in the sealing of the end flaps not being effected perfectly.

What is therefore needed is a method of facilitating the sealing of theend flaps of the film, the back flaps of which have already been securedtogether along the back of the object to be packed.

SUMMARY OF THE INVENTION It is accordingly an object of the presentinvention to provide a method and a means to carry out the method, bothcapable of meeting the above need and allowing a stable, ideal sealingof the end flaps of the film.

The present invention is directed to a seal of the end flaps of anon-rigid film which has already been sealed along at least the front,back, top or bottom of an object to be packed. According to theinvention, the method of facilitating the sealing of the film end flapsconsists of establishing a stream of air flowing toward the end flapsalong at least the top of the object, and training the end flaps of thefilm along the air flow, whereby the film end flaps are bent back into ahorizontally tensioned state favorable to the sealing thereof. A meansto carry out the above method comprises a plurality of air injectionnozzles arranged at least above the top of the object extending towardthe film end flaps partly along the top of the object.

Preferably, the sealing of the filrn end flaps is carried out by sealingequipment such as a compression packaging machine that has a conveyer totransfer the object to a predetermined position, a pressure platedisposed above the top of the object and moved toward the latter whenthe object reaches the predetermined position to press the object, andupper and lower seal bars movable between an operative position in whichthey pinch the end flaps of the back sealed film therebetween to effectthe sealing thereof and an inoperative position. In the case of suchsealing equipment, the plurality of air injection nozzles can be mountedon the pressure plate to extend toward the film end flaps. In addition,the sealing equipment may comprise a magnet mounted on the lower sealbar, and a holding-up member movable into a space defined by the endflaps and one end of the object before the lower seal bar is broughtinto the operative position, the holding-up member being made ofmagnetic material so that when 2 the lower seal bar with the magnet ismoved into the operative position, the holding-up member is attracted bythe magnet to hold up the end flaps of the film. In this case, theinsertion of the holding-up member into the associated space can beeffected with ease because the upper end flap of the film is held in ahorizontally tensioned state by the air stream.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of anobject to be wrapped in a film which has already been sealed along theback of the object;

FIG. 1a is a perspective view of the object with the end flaps of thefilm partly folded;

FIGS. lb and 1c are perspective views showing different methods ofsecuring the end flaps by a heat seal;

FIG. M is a perspective view of the wrapped object having the end flapssecured together without folding as in FIG. la;

FIG. 2 is a view similiar to that of FIG. 1, in which a non-rigid filmhas been used as a packaging material;

FIG. 3 is a view for explaining one embodiment of film tensioning meansaccording to the invention;

FIGS. 4a, 4b and 4c are views of different embodiments of the filmtensioning means according to the invention;

FIG. 5 is a diagrammatic sectional view of the object having thenon-rigid film wound thereabout with the backward edges of the filmbeing secured together along the back of the object on a conveyer ofsealing equipment;

FIG. 6 is a sectional view of the object and related parts as viewed ona line VI VI of FIG. 5;

FIGS. 7 to 11 are views for explaining successive steps of the automaticsealing operation; and

FIG. 12 is a perspective view of the object after it has been completelywrapped in the non-rigid film.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Generally, when wrapping anobject 1 to be packed such, for example, as a stack of printed mattersuch as news papers and magagines in a packaging material 2 in the formof film, a method is used which consists of training the film 2 aboutthe front, top, back and bottom of the object 1 as shown in FIG. 1,folding end flaps 3 and 4 inwards after sealing the film 2 along theback of the object 1 in a not shown manner, and securing the upper andlower end flaps 3 together by a heat seal. In this case, front and backend flaps 4 are first folded as shown in FIG. 1a and thereafter theupper and lower end flaps 3 are folded inward and secured together by aheat seal as shown in FIGS. lb or 1c. If desired, the sealing of theupper and lower end flaps 3 can be effected, without preliminarilyfolding the front and back flaps 4, by pinching-the end flaps 3 betweena pair of upper and lower seal bars (which will be describedhereinafter) to form a seal as shown in F IG. 1d.

Where the sealing of the upper and lower end flaps 3 is efiected afterfolding the end flaps 3 and 4, if it is intended to carry out thefolding of the end flaps automatically, a complex and costly foldingmachine has to be employed. In addition, where the sealing of the endflaps 3 is effected directly, as shown in FIG. Id, by ut'ilizing thestiffness of the film, there is a disadvantage in that an undesirablesealing is produced because the stiffness changes depending on thelength and thickness of the end flap.

In particular, when employing a non-rigid or flexible film of a lowstiffness, the upper end flap 3 of the film bends down as shown in FIG.2 due to its own weight overcoming the stiffness of the film. Thus, whenemploying the non-rigid film, such a favorable configuration of thewrapping film as shown in FIG. 1 can not be obtained. It will beunderstood that the bend of the upper end flap 3 causes inconvenience inthe next step of the packaging operation, resulting in the sealing ofthe end flaps not being effected perfectly.

Referring to FIG. 3, there is shown one embodiment of a film tensioningmeans according to the invention, wherein an air supply pipe 7 with aplurality of air injection nozzles 8 is arranged around a package 6. Theair injection nozzles 8 are circumferentially spaced and extend inopposite directions along and parallel to at least the top of thepackage 6 (in this example, the front,

back and bottom, in addition to the top), whereby when the air issupplied a plurality of air streams A are produced around the package 6,being directed toward the associated top, bottom, front and back flaps 3and 4 at a high speed. Therefore, the suspended end flaps 3 (FIG. 2) ofthe non-rigid film are trained along the air stream A and formed in asimilar contour to that of FIG. 1.

Of course, the object to be packed is not limited to a rectangular crosssection as shown in FIG. 3 and may be of a triangular, circular orspecial cross section as shown in FIGS. 4a, 4b and 4c, respectively.

Referring to FIGS. 5 to 11, there is shown automatic sealing equipmentfor securing the end flaps 3 of the film as shown in FIGS. 1d or 12, inwhich the method of tensioning the end flaps of the film is inaccordance with the invention.

In FIG. 5, the sealed package 6 which has been already sealed along itsback as shown at 2a by body sealing equipment (not shown) is transferredin a direction B to be fed to the automatic film end-fiap sealingequipment, in which the package 6 rides on a conveyer 9 to therebytravel until it bears against a stop 10. The conveyer 9 is adapted tostop when the package 6 reaches the stop 10 to set the position of thepackage 6. The cross section as viewed on the line VI VI of FIG. 5 isshown in FIG. 6, from which it is seen that the upper end flaps 3 of thefilm 2 extending respectively in the opposite directions are bent downdue to their own weight.

The package 6 in the stopped position of FIG. 5 is pressed down by apressure plate 11 when it descends in a direction C as shown in FIG. 7.The vertical movement of the pressure plate 11 is caused by a forceexerted from a suitable mechanism and this force exerted on the package6 is received by a plurality of rollers 12 flush with a pair of conveyerbelts 9a spaced a distance so as to accommodate the rollers 12therebetween. The pressure plate 11 is provided at the enlarged endportions with suitable bores (not shown) to receive associated airsupply tubes 7, and at the ends with a plurality of nozzles 8 (only oneis illustrated for one end) communicating with the associated bores.Therefore, simul-v taneously with the arrival of the pressure plate 11on the top of the package 6, the air is ejected from each nozzle 8 in adirection H along the top of the package 6. By thusly injecting the air,the upper end flap 3 of the film 2 is returned in a direction K as shownin FIG. 8

according to Bernoullis theorem and held in a horizontally tensionedposition.

The film end-flap sealing equipment further comprises a means forholding-up end flaps 3 of the film 2 which-includes a pair of movableholding-up members 13 (FIG. 8) made of magnetic material such, forexample, as Fe, Ni, Co, and their alloys and positioned close to thelefthand and righthand end flaps 3 of the film. If desired, theholding-up member may be provided with a magnet instead of being made ofthe magnetic material. When it is desired to secure the upper and lowerend flaps 3 together, the holding-up members 13 are moved in a suitablemanner in the opposite directions D (FIG. 9) so that their free endportions are inserted through the openings into associated spaces 2defined by one end of the object 1 and the upper and lower end flaps 3of the film 2 held in the horizontally tensioned position. This state isshown in FIG. 9. After the holding-up members 13 are disposed in therespective predetermined positions in the above manner, each lower sealbar 14 (FIG. 10) is first turned in a direction F. At this time, amagnet 15 mounted on the lower seal bar 14 attracts the associatedholding-up member 12 through the lower end flap 3 of the film.Therefore, after the holding-up member 13 is attracted by the magnet 15,the holding-up member 13 and the lower seal bar 14 are moved upwardly asa whole while pinching the lower end flap 3 therebetween. As a result,the holding-up member 13 is also turned in a direction E. Then, upperseal bars 16 (FIG. 11) are moved in a direction G so that the upper andlower end flaps 3 of the film are secured together by the heat seal. Asthe upper and lower end flaps 3 are guided by the holding-up member 13when the seal bars 15 and 16 are turned in the directions G and Frespectively, the heat sealing of the end flaps of the film takes placein a sure and certain manner. The object 1 thus wrapped has a goodconfiguration as shown in FIG. 12 because the end flaps 3 are securedtogether perfectly and surely.

From the foregoing, it will be understood that, according to the presentinvention, in effecting the sealing of the film for packaging, the endflaps of the film can be held in a substantially horizontally tensionedstate by the air stream, so that a good profile of the film favorable tothe heat seal can be obtained even in the case of a non-rigid film. Inaddition, since the end flaps of the film are forced upwards by the airjet, the holding-up member can be surely inserted between the upper andlower end flaps. Thereafter, the upper and lower end flaps are forcedinwards while being guided by the holding-up member, so that the endflaps can be surely overlapped each other immediately before theirsealing, with the result that a seal portion having a high seal strengthcan be obtained.

I claim:

1. In a sealing apparatus for heat sealing upper and lower end flaps atthe left and right-hand openings of a bag of a film having insufficientrigidity to be formsustaining and containing an object, and saidapparatus having a conveyer to transfer the bag wrapped around andsealed along at least the back of the object to be wrapped to apredetermined position where the upper and lower end flaps are to besecured together, means for facilitating sealing of the end flaps of thebag comprising a vertically movable pressure plate movable toward andaway from said conveyer to press the bag and the object against theconveyer when it reaches said and two pairs of upper and one for saidleft-hand and one for said predetermined position, lower seal bars,

right-hand opening,'said paired bars being movable be-' 2. A sealingapparatus according to claim 1 further comprising means for holding upthe lower end flaps to facilitate the sealing of said end flaps oversaid openings, said holding up means comprising a pair of magneticholding up members movable into corresponding spaces defined by theupper and lower end flaps of said left and right-hand openings beforesaid lower seal bars are brought into said operative position, and amagnet' on each lower seal bar, whereby when each lower seal bar isbrought from said inoperative position into said operative position thecorresponding holding up members and lower seal bars attract each andgrip the corresponding lower end flap therebetween to thereby hold upthe lower end flaps of the bag.

1. In a sealing apparatus for heat sealing upper and lower end flaps atthe left and right-hand openings of a bag of a film having insufficientrigidity to be form-sustaining and containing an object, and saidapparatus having a conveyer to transfer the bag wrapped around andsealed along at least the back of the object to be wrapped to apredetermined position where the upper and lower end flaps are to besecured together, means for facilitating sealing of the end flaps of thebag comprising a vertically movable pressure plate movable toward andaway from said conveyer to press the bag and the object against theconveyer when it reaches said predetermined position, and two pairs ofupper and lower seal bars, one for said left-hand and one for saidright-hand opening, said paired bars being movable between an operativeposition in which they pinch the corresponding upper and lower end flapsto effect the sealing thereof and an inoperative position, said pressureplate having an air passage therein and air blast nozzles thereonextending substantially horizontally toward the left and right-handupper end flaps along the top of the bag, and an air supply pipeconnected to said air passage.
 2. A sealing apparatus according to claim1 further comprising means for holding up the lower end flaps tofacilitate the sealing of said end flaps over said openings, saidholding up means comprising a pair of magnetic holding up membersmovable into corresponding spaces defined by the upper and lower endflaps of said left and right-haNd openings before said lower seal barsare brought into said operative position, and a magnet on each lowerseal bar, whereby when each lower seal bar is brought from saidinoperative position into said operative position the correspondingholding up members and lower seal bars attract each and grip thecorresponding lower end flap therebetween to thereby hold up the lowerend flaps of the bag.